What is the history and development of cellulose insulation in oil-filled power transformers?

The history and development of cellulose insulation in oil-filled power transformers date back to the early 20th century when natural materials were sought for electrical insulation. Cellulose, derived from wood pulp, became popular due to its excellent dielectric properties and thermal stability. Over the decades, advancements in processing and treatment techniques improved its performance, leading to its widespread use in oil-filled power transformers, where it effectively complements transformer oil in providing insulation and cooling.